The patch titled
vfs-lseekfd-0-seek_cur-race-condition-fix
has been added to the -mm tree. Its filename is
vfs-lseekfd-0-seek_cur-race-condition-fix.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: vfs-lseekfd-0-seek_cur-race-condition-fix
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
- fix coding-style
- fix default_llseek() as well
- add comments
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Alain Knaff <alain@xxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/read_write.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff -puN fs/read_write.c~vfs-lseekfd-0-seek_cur-race-condition-fix fs/read_write.c
--- a/fs/read_write.c~vfs-lseekfd-0-seek_cur-race-condition-fix
+++ a/fs/read_write.c
@@ -50,6 +50,14 @@ generic_file_llseek_unlocked(struct file
offset += inode->i_size;
break;
case SEEK_CUR:
+ /*
+ * Here we special-case the lseek(fd, 0, SEEK_CUR)
+ * position-querying operation. Avoid rewriting the "same"
+ * f_pos value back to the file because a concurrent read(),
+ * write() or lseek() might have altered it
+ */
+ if (offset == 0)
+ return file->f_pos;
offset += file->f_pos;
break;
}
@@ -105,8 +113,14 @@ loff_t default_llseek(struct file *file,
offset += i_size_read(file->f_path.dentry->d_inode);
break;
case SEEK_CUR:
- if(offset == 0)
- return file->f_pos;
+ /*
+ * See SEEK_CUR description in
+ * generic_file_llseek_unlocked()
+ */
+ if (offset == 0) {
+ retval = file->f_pos;
+ goto out;
+ }
offset += file->f_pos;
}
retval = -EINVAL;
@@ -117,6 +131,7 @@ loff_t default_llseek(struct file *file,
}
retval = offset;
}
+out:
unlock_kernel();
return retval;
}
_
Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are
cpusets-update-mems-allowed-in-page-allocator-fix.patch
remove-ratelimt.patch
doc-add-printk-formatstxt-fix.patch
kernel-kprobesc-dont-pad-kretprobe_table_locks-on-uniprocessor-builds.patch
rtc-rtc-wm8350-add-support-for-wm8350-rtc.patch
rtc-basic-implementation-of-epson-rx-8581-i2c-real-time-clock.patch
w1-export-w1_read_8-function-checkpatch-fixes.patch
mm-remove-the-might_sleep-from-lock_page.patch
linux-next.patch
next-remove-localversion.patch
arch-x86-kernel-setupc-omit-dmi_low_memory_corruption-when-it-is-unneeded.patch
tick-schedc-suppress-needless-timer-reprogramming.patch
linux-timexh-cleanup-for-userspace.patch
drivers-input-touchscreen-ucb1400_tsc-needs-gpio.patch
input-ad7879-fix-workaroud-build-error-reported-by-andrew-morton.patch
pci-uninline-pci_ioremap_bar.patch
pcie-add-option-to-passively-listen-for-pcie-hotplug-events-checkpatch-fixes.patch
align-avoid-evaluating-its-argument-twice.patch
vfs-lseekfd-0-seek_cur-race-condition-fix.patch
bdi-register-sysfs-bdi-device-only-once-per-queue-fix.patch
scsi-dpt_i2o-is-bust-on-ia64.patch
alsa-fix-snd_bug_on-and-friends.patch
mm-invoke-oom-killer-from-page-fault-fix.patch
mm-invoke-oom-killer-from-page-fault-fix-fix-2.patch
mm-write_cache_pages-more-terminate-quickly.patch
init-properly-placing-noinline-keyword.patch
binfmtsh-include-listh-fix.patch
spi_gpio-driver-cleanups.patch
quota-permit-separately-enabling-quota-accounting-and-enforcing-limits-fix.patch
quota-move-quotaio_vh-from-include-linux-to-fs-fix.patch
quota-move-quotaio_vh-from-include-linux-to-fs-fix-2.patch
quota-convert-union-in-mem_dqinfo-to-a-pointer-cleanup.patch
quota-support-64-bit-quota-format-fix.patch
quota-support-64-bit-quota-format-fix-2.patch
memcg-introduce-charge-commit-cancel-style-of-functions-fix.patch
edac-struct-device-replace-bus_id-with-dev_name-dev_set_name-checkpatch-fixes.patch
edac-x38-use-the-architectures-readq-function-fix.patch
filesystem-freeze-implement-generic-freeze-feature-fix.patch
nilfs2-inode-operations-fix.patch
nilfs2-pathname-operations-fix.patch
nilfs2-super-block-operations-fix.patch
reiser4.patch
reiser4-tree_lock-fixes.patch
reiser4-tree_lock-fixes-fix.patch
reiser4-semaphore-fix.patch
slb-drop-kmem-cache-argument-from-constructor-reiser4.patch
reiser4-suid.patch
reiser4-track-upstream-changes.patch
reiser4-broke.patch
nr_blockdev_pages-in_interrupt-warning.patch
slab-leaks3-default-y.patch
put_bh-debug.patch
shrink_slab-handle-bad-shrinkers.patch
getblk-handle-2tb-devices.patch
getblk-handle-2tb-devices-fix.patch
undeprecate-pci_find_device.patch
notify_change-callers-must-hold-i_mutex.patch
profile-likely-unlikely-macros.patch
drivers-net-bonding-bond_sysfsc-suppress-uninitialized-var-warning.patch
w1-build-fix.patch
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